This invention relates to an apparatus for holding a stack of sheets, such as bank notes, in a sheet counting machine.
A known sheet counting machine for counting the number of sheets has a rotatable holder for holding thereon a stack of sheets, bank notes, for example, to be counted, and a plurality of rotary suction heads carried on a rotary cylinder for attracting the bank notes by suction and deflecting each sheet one after another away from the stack of bank notes. The stack of bank notes held on the holder must be pressed with a suitably selected pressing force against the suction heads so that the bank notes may be effectively attracted by the suction heads. If the pressing force of the stack of bank notes against the suction head is too strong, the stack will be repeatedly bounced on the suction head, causing undesirable noise and also premature wear of the suction heads. On the contrary, if the pressing force is too weak, the bank notes cannot have sufficient contact with the suction head, thus causing a considerable amount of air to be introduced into the suction head and thereby making the counting operation of the machine to be inefficient. Thus, the pressing force of the stack of bank notes against the suction heads must be adjusted to a suitable level. In the prior art sheet counting machine of such type, however, proper adjustment of the pressing force of the stack of sheets against the suction heads has been not easy to achieve, and such adjustments have had to rely on the skills of an experienced engineer.